Power and data interfaces are widely used in many devices to transfer data and power from an external source. These interfaces are particularly desirable for use with devices that are stored for a period of time and need to be activated quickly. An example of such a device is a missile used in combat operations.
A data interface may be used to download data, such as crypto keys for the missile's Global Positioning System ("GPS"), prior to deployment. The data is downloaded quickly in order to launch the missiles at a rapid rate. Further, each missile is initialized with the GPS keys prior to launch so that the keys may be scrambled to evade electronic counter measures. The downloaded key data then may be used in decoding the GPS signals received from satellites in guiding the missile to its target.
Electronic circuitry on the missile may be connected to a chemical battery that is ignited immediately prior to the missile's deployment. The battery supplies power to the GPS circuitry and other devices. In igniting the battery, chemicals are mixed and/or combined to provide power. Thus, the battery may be dormant until it is activated. This allows a longer shelf life for the battery and the missile electronics.
Interfaces have been provided that ignite the battery and download data into a secondary device, such as a missile. Devices that utilize electrical connections and/or mechanical connections are not reliable in harsh environments associated with military operations. The operability of these connectors may be affected by dirt, hydraulic fluid, salt, moisture, and other contaminates. Further, electrical and mechanical connectors may require accurate alignment between the two assemblies that are being interfaced. Slip rings have been incorporated to avoid the need for connectors. Slip rings, however, are susceptible to corrosion and have reliability problems in harsh environments. Other devices have utilized an inductive coupling system without magnetic cores, but, without the magnetic cores, no significant power may be transferred, and the data transfer rate is restricted to 1 KHz. Air core transformers also have been utilized as connectorless interfaces. Air core transformers also transfer data and power at a rate slower than that desired for high speed operations, such as missile deployments. Moreover, power and data are not able to transfer across the interface in adequate amounts. Thus, these techniques are susceptible to reliability problems in harsh environments and corrosion, or do not provide a data and power transfer capability required to perform high speed operations.